//     Backbone.js 0.9.2

//     (c) 2010-2012 Jeremy Ashkenas, DocumentCloud Inc.
//     Backbone may be freely distributed under the MIT license.
//     For all details and documentation:
//     http://backbonejs.org

(function(){

// Initial Setup
// -------------

// Save a reference to the global object (`window` in the browser, `global`
// on the server).
var root = this;

// Save the previous value of the `Backbone` variable, so that it can be
// restored later on, if `noConflict` is used.
var previousBackbone = root.Backbone;

// Create a local reference to slice/splice.
var slice = Array.prototype.slice;
var splice = Array.prototype.splice;

// The top-level namespace. All public Backbone classes and modules will
// be attached to this. Exported for both CommonJS and the browser.
var Backbone;
if (typeof exports !== 'undefined') {
	Backbone = exports;
} else {
	Backbone = root.Backbone = {};
}

// Current version of the library. Keep in sync with `package.json`.
Backbone.VERSION = '0.9.2';

// Require Underscore, if we're on the server, and it's not already present.
var _ = root._;
if (!_ && (typeof require !== 'undefined')) _ = require('/alloy/underscore');

// For Backbone's purposes, jQuery, Zepto, or Ender owns the `$` variable.
var $ = root.jQuery || root.Zepto || root.ender;

// Set the JavaScript library that will be used for DOM manipulation and
// Ajax calls (a.k.a. the `$` variable). By default Backbone will use: jQuery,
// Zepto, or Ender; but the `setDomLibrary()` method lets you inject an
// alternate JavaScript library (or a mock library for testing your views
// outside of a browser).
Backbone.setDomLibrary = function(lib) {
	$ = lib;
};

// Runs Backbone.js in *noConflict* mode, returning the `Backbone` variable
// to its previous owner. Returns a reference to this Backbone object.
Backbone.noConflict = function() {
	root.Backbone = previousBackbone;
	return this;
};

// Turn on `emulateHTTP` to support legacy HTTP servers. Setting this option
// will fake `"PUT"` and `"DELETE"` requests via the `_method` parameter and
// set a `X-Http-Method-Override` header.
Backbone.emulateHTTP = false;

// Turn on `emulateJSON` to support legacy servers that can't deal with direct
// `application/json` requests ... will encode the body as
// `application/x-www-form-urlencoded` instead and will send the model in a
// form param named `model`.
Backbone.emulateJSON = false;

// Backbone.Events
// -----------------

// Regular expression used to split event strings
var eventSplitter = /\s+/;

// A module that can be mixed in to *any object* in order to provide it with
// custom events. You may bind with `on` or remove with `off` callback functions
// to an event; trigger`-ing an event fires all callbacks in succession.
//
//     var object = {};
//     _.extend(object, Backbone.Events);
//     object.on('expand', function(){ alert('expanded'); });
//     object.trigger('expand');
//
var Events = Backbone.Events = {

	// Bind one or more space separated events, `events`, to a `callback`
	// function. Passing `"all"` will bind the callback to all events fired.
	on: function(events, callback, context) {

	var calls, event, node, tail, list;
	if (!callback) return this;
	events = events.split(eventSplitter);
	calls = this._callbacks || (this._callbacks = {});

	// Create an immutable callback list, allowing traversal during
	// modification.  The tail is an empty object that will always be used
	// as the next node.
	while (event = events.shift()) {
		list = calls[event];
		node = list ? list.tail : {};
		node.next = tail = {};
		node.context = context;
		node.callback = callback;
		calls[event] = {tail: tail, next: list ? list.next : node};
	}

	return this;
	},

	// Remove one or many callbacks. If `context` is null, removes all callbacks
	// with that function. If `callback` is null, removes all callbacks for the
	// event. If `events` is null, removes all bound callbacks for all events.
	off: function(events, callback, context) {
	var event, calls, node, tail, cb, ctx;

	// No events, or removing *all* events.
	if (!(calls = this._callbacks)) return;
	if (!(events || callback || context)) {
		delete this._callbacks;
		return this;
	}

	// Loop through the listed events and contexts, splicing them out of the
	// linked list of callbacks if appropriate.
	events = events ? events.split(eventSplitter) : _.keys(calls);
	while (event = events.shift()) {
		node = calls[event];
		delete calls[event];
		if (!node || !(callback || context)) continue;
		// Create a new list, omitting the indicated callbacks.
		tail = node.tail;
		while ((node = node.next) !== tail) {
		cb = node.callback;
		ctx = node.context;
		if ((callback && cb !== callback) || (context && ctx !== context)) {
			this.on(event, cb, ctx);
		}
		}
	}

	return this;
	},

	// Trigger one or many events, firing all bound callbacks. Callbacks are
	// passed the same arguments as `trigger` is, apart from the event name
	// (unless you're listening on `"all"`, which will cause your callback to
	// receive the true name of the event as the first argument).
	trigger: function(events) {
	var event, node, calls, tail, args, all, rest;
	if (!(calls = this._callbacks)) return this;
	all = calls.all;
	events = events.split(eventSplitter);
	rest = slice.call(arguments, 1);

	// For each event, walk through the linked list of callbacks twice,
	// first to trigger the event, then to trigger any `"all"` callbacks.
	while (event = events.shift()) {
		if (node = calls[event]) {
		tail = node.tail;
		while ((node = node.next) !== tail) {
			node.callback.apply(node.context || this, rest);
		}
		}
		if (node = all) {
		tail = node.tail;
		args = [event].concat(rest);
		while ((node = node.next) !== tail) {
			node.callback.apply(node.context || this, args);
		}
		}
	}

	return this;
	}

};

// Aliases for backwards compatibility.
Events.bind   = Events.on;
Events.unbind = Events.off;

// Backbone.Model
// --------------

// Create a new model, with defined attributes. A client id (`cid`)
// is automatically generated and assigned for you.
var Model = Backbone.Model = function(attributes, options) {
	var defaults;
	attributes || (attributes = {});
	if (options && options.parse) attributes = this.parse(attributes);
	if (defaults = getValue(this, 'defaults')) {
	attributes = _.extend({}, defaults, attributes);
	}
	if (options && options.collection) this.collection = options.collection;
	this.attributes = {};
	this._escapedAttributes = {};
	this.cid = _.uniqueId('c');
	this.changed = {};
	this._silent = {};
	this._pending = {};
	this.set(attributes, {silent: true});
	// Reset change tracking.
	this.changed = {};
	this._silent = {};
	this._pending = {};
	this._previousAttributes = _.clone(this.attributes);
	this.initialize.apply(this, arguments);
};

// Attach all inheritable methods to the Model prototype.
_.extend(Model.prototype, Events, {

	// A hash of attributes whose current and previous value differ.
	changed: null,

	// A hash of attributes that have silently changed since the last time
	// `change` was called.  Will become pending attributes on the next call.
	_silent: null,

	// A hash of attributes that have changed since the last `'change'` event
	// began.
	_pending: null,

	// The default name for the JSON `id` attribute is `"id"`. MongoDB and
	// CouchDB users may want to set this to `"_id"`.
	idAttribute: 'id',

	// Initialize is an empty function by default. Override it with your own
	// initialization logic.
	initialize: function(){},

	// Return a copy of the model's `attributes` object.
	toJSON: function(options) {
	return _.clone(this.attributes);
	},

	// Get the value of an attribute.
	get: function(attr) {
	return this.attributes[attr];
	},

	// Get the HTML-escaped value of an attribute.
	escape: function(attr) {
	var html;
	if (html = this._escapedAttributes[attr]) return html;
	var val = this.get(attr);
	return this._escapedAttributes[attr] = _.escape(val == null ? '' : '' + val);
	},

	// Returns `true` if the attribute contains a value that is not null
	// or undefined.
	has: function(attr) {
	return this.get(attr) != null;
	},

	// Set a hash of model attributes on the object, firing `"change"` unless
	// you choose to silence it.
	set: function(key, value, options) {
	var attrs, attr, val;

	// Handle both
	if (_.isObject(key) || key == null) {
		attrs = key;
		options = value;
	} else {
		attrs = {};
		attrs[key] = value;
	}

	// Extract attributes and options.
	options || (options = {});
	if (!attrs) return this;
	if (attrs instanceof Model) attrs = attrs.attributes;
	if (options.unset) for (attr in attrs) attrs[attr] = void 0;

	// Run validation.
	if (!this._validate(attrs, options)) return false;

	// Check for changes of `id`.
	if (this.idAttribute in attrs) this.id = attrs[this.idAttribute];

	var changes = options.changes = {};
	var now = this.attributes;
	var escaped = this._escapedAttributes;
	var prev = this._previousAttributes || {};

	// For each `set` attribute...
	for (attr in attrs) {
		val = attrs[attr];

		// If the new and current value differ, record the change.
		if (!_.isEqual(now[attr], val) || (options.unset && _.has(now, attr))) {
		delete escaped[attr];
		(options.silent ? this._silent : changes)[attr] = true;
		}

		// Update or delete the current value.
		options.unset ? delete now[attr] : now[attr] = val;

		// If the new and previous value differ, record the change.  If not,
		// then remove changes for this attribute.
		if (!_.isEqual(prev[attr], val) || (_.has(now, attr) != _.has(prev, attr))) {
		this.changed[attr] = val;
		if (!options.silent) this._pending[attr] = true;
		} else {
		delete this.changed[attr];
		delete this._pending[attr];
		}
	}

	// Fire the `"change"` events.
	if (!options.silent) this.change(options);
	return this;
	},

	// Remove an attribute from the model, firing `"change"` unless you choose
	// to silence it. `unset` is a noop if the attribute doesn't exist.
	unset: function(attr, options) {
	(options || (options = {})).unset = true;
	return this.set(attr, null, options);
	},

	// Clear all attributes on the model, firing `"change"` unless you choose
	// to silence it.
	clear: function(options) {
	(options || (options = {})).unset = true;
	return this.set(_.clone(this.attributes), options);
	},

	// Fetch the model from the server. If the server's representation of the
	// model differs from its current attributes, they will be overriden,
	// triggering a `"change"` event.
	fetch: function(options) {
	options = options ? _.clone(options) : {};
	var model = this;
	var success = options.success;
	options.success = function(resp, status, xhr) {
		if (!model.set(model.parse(resp, xhr), options)) return false;
		if (success) success(model, resp);
	};
	options.error = Backbone.wrapError(options.error, model, options);
	return (this.sync || Backbone.sync).call(this, 'read', this, options);
	},

	// Set a hash of model attributes, and sync the model to the server.
	// If the server returns an attributes hash that differs, the model's
	// state will be `set` again.
	save: function(key, value, options) {
	var attrs, current;

	// Handle both `("key", value)` and `({key: value})` -style calls.
	if (_.isObject(key) || key == null) {
		attrs = key;
		options = value;
	} else {
		attrs = {};
		attrs[key] = value;
	}
	options = options ? _.clone(options) : {};

	// If we're "wait"-ing to set changed attributes, validate early.
	if (options.wait) {
		if (!this._validate(attrs, options)) return false;
		current = _.clone(this.attributes);
	}

	// Regular saves `set` attributes before persisting to the server.
	var silentOptions = _.extend({}, options, {silent: true});
	if (attrs && !this.set(attrs, options.wait ? silentOptions : options)) {
		return false;
	}

	// After a successful server-side save, the client is (optionally)
	// updated with the server-side state.
	var model = this;
	var success = options.success;
	options.success = function(resp, status, xhr) {
		var serverAttrs = model.parse(resp, xhr);
		if (options.wait) {
		delete options.wait;
		serverAttrs = _.extend(attrs || {}, serverAttrs);
		}
		if (!model.set(serverAttrs, options)) return false;
		if (success) {
		success(model, resp);
		} else {
		model.trigger('sync', model, resp, options);
		}
	};

	// Finish configuring and sending the Ajax request.
	options.error = Backbone.wrapError(options.error, model, options);
	var method = this.isNew() ? 'create' : 'update';
	var xhr = (this.sync || Backbone.sync).call(this, method, this, options);
	if (options.wait) this.set(current, silentOptions);
	return xhr;
	},

	// Destroy this model on the server if it was already persisted.
	// Optimistically removes the model from its collection, if it has one.
	// If `wait: true` is passed, waits for the server to respond before removal.
	destroy: function(options) {
	options = options ? _.clone(options) : {};
	var model = this;
	var success = options.success;

	var triggerDestroy = function() {
		model.trigger('destroy', model, model.collection, options);
	};

	if (this.isNew()) {
		triggerDestroy();
		return false;
	}

	options.success = function(resp) {
		if (options.wait) triggerDestroy();
		if (success) {
		success(model, resp);
		} else {
		model.trigger('sync', model, resp, options);
		}
	};

	options.error = Backbone.wrapError(options.error, model, options);
	var xhr = (this.sync || Backbone.sync).call(this, 'delete', this, options);
	if (!options.wait) triggerDestroy();
	return xhr;
	},

	// Default URL for the model's representation on the server -- if you're
	// using Backbone's restful methods, override this to change the endpoint
	// that will be called.
	url: function() {
	var base = getValue(this, 'urlRoot') || getValue(this.collection, 'url') || urlError();
	if (this.isNew()) return base;
	return base + (base.charAt(base.length - 1) == '/' ? '' : '/') + encodeURIComponent(this.id);
	},

	// **parse** converts a response into the hash of attributes to be `set` on
	// the model. The default implementation is just to pass the response along.
	parse: function(resp, xhr) {
	return resp;
	},

	// Create a new model with identical attributes to this one.
	clone: function() {
	return new this.constructor(this.attributes);
	},

	// A model is new if it has never been saved to the server, and lacks an id.
	isNew: function() {
	return this.id == null;
	},

	// Call this method to manually fire a `"change"` event for this model and
	// a `"change:attribute"` event for each changed attribute.
	// Calling this will cause all objects observing the model to update.
	change: function(options) {
	options || (options = {});
	var changing = this._changing;
	this._changing = true;

	// Silent changes become pending changes.
	for (var attr in this._silent) this._pending[attr] = true;

	// Silent changes are triggered.
	var changes = _.extend({}, options.changes, this._silent);
	this._silent = {};
	for (var attr in changes) {
		this.trigger('change:' + attr, this, this.get(attr), options);
	}
	if (changing) return this;

	// Continue firing `"change"` events while there are pending changes.
	while (!_.isEmpty(this._pending)) {
		this._pending = {};
		this.trigger('change', this, options);
		// Pending and silent changes still remain.
		for (var attr in this.changed) {
		if (this._pending[attr] || this._silent[attr]) continue;
		delete this.changed[attr];
		}
		this._previousAttributes = _.clone(this.attributes);
	}

	this._changing = false;
	return this;
	},

	// Determine if the model has changed since the last `"change"` event.
	// If you specify an attribute name, determine if that attribute has changed.
	hasChanged: function(attr) {
	if (!arguments.length) return !_.isEmpty(this.changed);
	return _.has(this.changed, attr);
	},

	// Return an object containing all the attributes that have changed, or
	// false if there are no changed attributes. Useful for determining what
	// parts of a view need to be updated and/or what attributes need to be
	// persisted to the server. Unset attributes will be set to undefined.
	// You can also pass an attributes object to diff against the model,
	// determining if there *would be* a change.
	changedAttributes: function(diff) {
	if (!diff) return this.hasChanged() ? _.clone(this.changed) : false;
	var val, changed = false, old = this._previousAttributes;
	for (var attr in diff) {
		if (_.isEqual(old[attr], (val = diff[attr]))) continue;
		(changed || (changed = {}))[attr] = val;
	}
	return changed;
	},

	// Get the previous value of an attribute, recorded at the time the last
	// `"change"` event was fired.
	previous: function(attr) {
	if (!arguments.length || !this._previousAttributes) return null;
	return this._previousAttributes[attr];
	},

	// Get all of the attributes of the model at the time of the previous
	// `"change"` event.
	previousAttributes: function() {
	return _.clone(this._previousAttributes);
	},

	// Check if the model is currently in a valid state. It's only possible to
	// get into an *invalid* state if you're using silent changes.
	isValid: function() {
	return !this.validate(this.attributes);
	},

	// Run validation against the next complete set of model attributes,
	// returning `true` if all is well. If a specific `error` callback has
	// been passed, call that instead of firing the general `"error"` event.
	_validate: function(attrs, options) {
	if (options.silent || !this.validate) return true;
	attrs = _.extend({}, this.attributes, attrs);
	var error = this.validate(attrs, options);
	if (!error) return true;
	if (options && options.error) {
		options.error(this, error, options);
	} else {
		this.trigger('error', this, error, options);
	}
	return false;
	}

});

// Backbone.Collection
// -------------------

// Provides a standard collection class for our sets of models, ordered
// or unordered. If a `comparator` is specified, the Collection will maintain
// its models in sort order, as they're added and removed.
var Collection = Backbone.Collection = function(models, options) {
	options || (options = {});
	if (options.model) this.model = options.model;
	if (options.comparator) this.comparator = options.comparator;
	this._reset();
	this.initialize.apply(this, arguments);
	if (models) this.reset(models, {silent: true, parse: options.parse});
};

// Define the Collection's inheritable methods.
_.extend(Collection.prototype, Events, {

	// The default model for a collection is just a **Backbone.Model**.
	// This should be overridden in most cases.
	model: Model,

	// Initialize is an empty function by default. Override it with your own
	// initialization logic.
	initialize: function(){},

	// The JSON representation of a Collection is an array of the
	// models' attributes.
	toJSON: function(options) {
	return this.map(function(model){ return model.toJSON(options); });
	},

	// Add a model, or list of models to the set. Pass **silent** to avoid
	// firing the `add` event for every new model.
	add: function(models, options) {
	var i, index, length, model, cid, id, cids = {}, ids = {}, dups = [];
	options || (options = {});
	models = _.isArray(models) ? models.slice() : [models];

	// Begin by turning bare objects into model references, and preventing
	// invalid models or duplicate models from being added.
	for (i = 0, length = models.length; i < length; i++) {
		if (!(model = models[i] = this._prepareModel(models[i], options))) {
		throw new Error("Can't add an invalid model to a collection");
		}
		cid = model.cid;
		id = model.id;
		if (cids[cid] || this._byCid[cid] || ((id != null) && (ids[id] || this._byId[id]))) {
		dups.push(i);
		continue;
		}
		cids[cid] = ids[id] = model;
	}

	// Remove duplicates.
	i = dups.length;
	while (i--) {
		models.splice(dups[i], 1);
	}

	// Listen to added models' events, and index models for lookup by
	// `id` and by `cid`.
	for (i = 0, length = models.length; i < length; i++) {
		(model = models[i]).on('all', this._onModelEvent, this);
		this._byCid[model.cid] = model;
		if (model.id != null) this._byId[model.id] = model;
	}

	// Insert models into the collection, re-sorting if needed, and triggering
	// `add` events unless silenced.
	this.length += length;
	index = options.at != null ? options.at : this.models.length;
	splice.apply(this.models, [index, 0].concat(models));
	if (this.comparator) this.sort({silent: true});
	if (options.silent) return this;
	for (i = 0, length = this.models.length; i < length; i++) {
		if (!cids[(model = this.models[i]).cid]) continue;
		options.index = i;
		model.trigger('add', model, this, options);
	}
	return this;
	},

	// Remove a model, or a list of models from the set. Pass silent to avoid
	// firing the `remove` event for every model removed.
	remove: function(models, options) {
	var i, l, index, model;
	options || (options = {});
	models = _.isArray(models) ? models.slice() : [models];
	for (i = 0, l = models.length; i < l; i++) {
		model = this.getByCid(models[i]) || this.get(models[i]);
		if (!model) continue;
		delete this._byId[model.id];
		delete this._byCid[model.cid];
		index = this.indexOf(model);
		this.models.splice(index, 1);
		this.length--;
		if (!options.silent) {
		options.index = index;
		model.trigger('remove', model, this, options);
		}
		this._removeReference(model);
	}
	return this;
	},

	// Add a model to the end of the collection.
	push: function(model, options) {
	model = this._prepareModel(model, options);
	this.add(model, options);
	return model;
	},

	// Remove a model from the end of the collection.
	pop: function(options) {
	var model = this.at(this.length - 1);
	this.remove(model, options);
	return model;
	},

	// Add a model to the beginning of the collection.
	unshift: function(model, options) {
	model = this._prepareModel(model, options);
	this.add(model, _.extend({at: 0}, options));
	return model;
	},

	// Remove a model from the beginning of the collection.
	shift: function(options) {
	var model = this.at(0);
	this.remove(model, options);
	return model;
	},

	// Get a model from the set by id.
	get: function(id) {
	if (id == null) return void 0;
	return this._byId[id.id != null ? id.id : id];
	},

	// Get a model from the set by client id.
	getByCid: function(cid) {
	return cid && this._byCid[cid.cid || cid];
	},

	// Get the model at the given index.
	at: function(index) {
	return this.models[index];
	},

	// Return models with matching attributes. Useful for simple cases of `filter`.
	where: function(attrs) {
	if (_.isEmpty(attrs)) return [];
	return this.filter(function(model) {
		for (var key in attrs) {
		if (attrs[key] !== model.get(key)) return false;
		}
		return true;
	});
	},

	// Force the collection to re-sort itself. You don't need to call this under
	// normal circumstances, as the set will maintain sort order as each item
	// is added.
	sort: function(options) {
	options || (options = {});
	if (!this.comparator) throw new Error('Cannot sort a set without a comparator');
	var boundComparator = _.bind(this.comparator, this);
	if (this.comparator.length == 1) {
		this.models = this.sortBy(boundComparator);
	} else {
		this.models.sort(boundComparator);
	}
	if (!options.silent) this.trigger('reset', this, options);
	return this;
	},

	// Pluck an attribute from each model in the collection.
	pluck: function(attr) {
	return _.map(this.models, function(model){ return model.get(attr); });
	},

	// When you have more items than you want to add or remove individually,
	// you can reset the entire set with a new list of models, without firing
	// any `add` or `remove` events. Fires `reset` when finished.
	reset: function(models, options) {
	models  || (models = []);
	options || (options = {});
	for (var i = 0, l = this.models.length; i < l; i++) {
		this._removeReference(this.models[i]);
	}
	this._reset();
	this.add(models, _.extend({silent: true}, options));
	if (!options.silent) this.trigger('reset', this, options);
	return this;
	},

	// Fetch the default set of models for this collection, resetting the
	// collection when they arrive. If `add: true` is passed, appends the
	// models to the collection instead of resetting.
	fetch: function(options) {
	options = options ? _.clone(options) : {};
	if (options.parse === undefined) options.parse = true;
	var collection = this;
	var success = options.success;
	options.success = function(resp, status, xhr) {
		collection[options.add ? 'add' : 'reset'](collection.parse(resp, xhr), options);
		if (success) success(collection, resp);
	};
	options.error = Backbone.wrapError(options.error, collection, options);
	return (this.sync || Backbone.sync).call(this, 'read', this, options);
	},

	// Create a new instance of a model in this collection. Add the model to the
	// collection immediately, unless `wait: true` is passed, in which case we
	// wait for the server to agree.
	create: function(model, options) {
	var coll = this;
	options = options ? _.clone(options) : {};
	model = this._prepareModel(model, options);
	if (!model) return false;
	if (!options.wait) coll.add(model, options);
	var success = options.success;
	options.success = function(nextModel, resp, xhr) {
		if (options.wait) coll.add(nextModel, options);
		if (success) {
		success(nextModel, resp);
		} else {
		nextModel.trigger('sync', model, resp, options);
		}
	};
	model.save(null, options);
	return model;
	},

	// **parse** converts a response into a list of models to be added to the
	// collection. The default implementation is just to pass it through.
	parse: function(resp, xhr) {
	return resp;
	},

	// Proxy to _'s chain. Can't be proxied the same way the rest of the
	// underscore methods are proxied because it relies on the underscore
	// constructor.
	chain: function () {
	return _(this.models).chain();
	},

	// Reset all internal state. Called when the collection is reset.
	_reset: function(options) {
	this.length = 0;
	this.models = [];
	this._byId  = {};
	this._byCid = {};
	},

	// Prepare a model or hash of attributes to be added to this collection.
	_prepareModel: function(model, options) {
	options || (options = {});
	if (!(model instanceof Model)) {
		var attrs = model;
		options.collection = this;
		model = new this.model(attrs, options);
		if (!model._validate(model.attributes, options)) model = false;
	} else if (!model.collection) {
		model.collection = this;
	}
	return model;
	},

	// Internal method to remove a model's ties to a collection.
	_removeReference: function(model) {
	if (this == model.collection) {
		delete model.collection;
	}
	model.off('all', this._onModelEvent, this);
	},

	// Internal method called every time a model in the set fires an event.
	// Sets need to update their indexes when models change ids. All other
	// events simply proxy through. "add" and "remove" events that originate
	// in other collections are ignored.
	_onModelEvent: function(event, model, collection, options) {
	if ((event == 'add' || event == 'remove') && collection != this) return;
	if (event == 'destroy') {
		this.remove(model, options);
	}
	if (model && event === 'change:' + model.idAttribute) {
		delete this._byId[model.previous(model.idAttribute)];
		this._byId[model.id] = model;
	}
	this.trigger.apply(this, arguments);
	}

});

// Underscore methods that we want to implement on the Collection.
var methods = ['forEach', 'each', 'map', 'reduce', 'reduceRight', 'find',
	'detect', 'filter', 'select', 'reject', 'every', 'all', 'some', 'any',
	'include', 'contains', 'invoke', 'max', 'min', 'sortBy', 'sortedIndex',
	'toArray', 'size', 'first', 'initial', 'rest', 'last', 'without', 'indexOf',
	'shuffle', 'lastIndexOf', 'isEmpty', 'groupBy'];

// Mix in each Underscore method as a proxy to `Collection#models`.
_.each(methods, function(method) {
	Collection.prototype[method] = function() {
	return _[method].apply(_, [this.models].concat(_.toArray(arguments)));
	};
});

// Backbone.Router
// -------------------

// Routers map faux-URLs to actions, and fire events when routes are
// matched. Creating a new one sets its `routes` hash, if not set statically.
var Router = Backbone.Router = function(options) {
	options || (options = {});
	if (options.routes) this.routes = options.routes;
	this._bindRoutes();
	this.initialize.apply(this, arguments);
};

// Cached regular expressions for matching named param parts and splatted
// parts of route strings.
var namedParam    = /:\w+/g;
var splatParam    = /\*\w+/g;
var escapeRegExp  = /[-[\]{}()+?.,\\^$|#\s]/g;

// Set up all inheritable **Backbone.Router** properties and methods.
_.extend(Router.prototype, Events, {

	// Initialize is an empty function by default. Override it with your own
	// initialization logic.
	initialize: function(){},

	// Manually bind a single named route to a callback. For example:
	//
	//     this.route('search/:query/p:num', 'search', function(query, num) {
	//       ...
	//     });
	//
	route: function(route, name, callback) {
	Backbone.history || (Backbone.history = new History);
	if (!_.isRegExp(route)) route = this._routeToRegExp(route);
	if (!callback) callback = this[name];
	Backbone.history.route(route, _.bind(function(fragment) {
		var args = this._extractParameters(route, fragment);
		callback && callback.apply(this, args);
		this.trigger.apply(this, ['route:' + name].concat(args));
		Backbone.history.trigger('route', this, name, args);
	}, this));
	return this;
	},

	// Simple proxy to `Backbone.history` to save a fragment into the history.
	navigate: function(fragment, options) {
	Backbone.history.navigate(fragment, options);
	},

	// Bind all defined routes to `Backbone.history`. We have to reverse the
	// order of the routes here to support behavior where the most general
	// routes can be defined at the bottom of the route map.
	_bindRoutes: function() {
	if (!this.routes) return;
	var routes = [];
	for (var route in this.routes) {
		routes.unshift([route, this.routes[route]]);
	}
	for (var i = 0, l = routes.length; i < l; i++) {
		this.route(routes[i][0], routes[i][1], this[routes[i][1]]);
	}
	},

	// Convert a route string into a regular expression, suitable for matching
	// against the current location hash.
	_routeToRegExp: function(route) {
	route = route.replace(escapeRegExp, '\\$&')
				.replace(namedParam, '([^\/]+)')
				.replace(splatParam, '(.*?)');
	return new RegExp('^' + route + '$');
	},

	// Given a route, and a URL fragment that it matches, return the array of
	// extracted parameters.
	_extractParameters: function(route, fragment) {
	return route.exec(fragment).slice(1);
	}

});

// Backbone.History
// ----------------

// Handles cross-browser history management, based on URL fragments. If the
// browser does not support `onhashchange`, falls back to polling.
var History = Backbone.History = function() {
	this.handlers = [];
	_.bindAll(this, 'checkUrl');
};

// Cached regex for cleaning leading hashes and slashes .
var routeStripper = /^[#\/]/;

// Cached regex for detecting MSIE.
var isExplorer = /msie [\w.]+/;

// Has the history handling already been started?
History.started = false;

// Set up all inheritable **Backbone.History** properties and methods.
_.extend(History.prototype, Events, {

	// The default interval to poll for hash changes, if necessary, is
	// twenty times a second.
	interval: 50,

	// Gets the true hash value. Cannot use location.hash directly due to bug
	// in Firefox where location.hash will always be decoded.
	getHash: function(windowOverride) {
	var loc = windowOverride ? windowOverride.location : window.location;
	var match = loc.href.match(/#(.*)$/);
	return match ? match[1] : '';
	},

	// Get the cross-browser normalized URL fragment, either from the URL,
	// the hash, or the override.
	getFragment: function(fragment, forcePushState) {
	if (fragment == null) {
		if (this._hasPushState || forcePushState) {
		fragment = window.location.pathname;
		var search = window.location.search;
		if (search) fragment += search;
		} else {
		fragment = this.getHash();
		}
	}
	if (!fragment.indexOf(this.options.root)) fragment = fragment.substr(this.options.root.length);
	return fragment.replace(routeStripper, '');
	},

	// Start the hash change handling, returning `true` if the current URL matches
	// an existing route, and `false` otherwise.
	start: function(options) {
	if (History.started) throw new Error("Backbone.history has already been started");
	History.started = true;

	// Figure out the initial configuration. Do we need an iframe?
	// Is pushState desired ... is it available?
	this.options          = _.extend({}, {root: '/'}, this.options, options);
	this._wantsHashChange = this.options.hashChange !== false;
	this._wantsPushState  = !!this.options.pushState;
	this._hasPushState    = !!(this.options.pushState && window.history && window.history.pushState);
	var fragment          = this.getFragment();
	var docMode           = document.documentMode;
	var oldIE             = (isExplorer.exec(navigator.userAgent.toLowerCase()) && (!docMode || docMode <= 7));

	if (oldIE) {
		this.iframe = $('<iframe src="javascript:0" tabindex="-1" />').hide().appendTo('body')[0].contentWindow;
		this.navigate(fragment);
	}

	// Depending on whether we're using pushState or hashes, and whether
	// 'onhashchange' is supported, determine how we check the URL state.
	if (this._hasPushState) {
		$(window).bind('popstate', this.checkUrl);
	} else if (this._wantsHashChange && ('onhashchange' in window) && !oldIE) {
		$(window).bind('hashchange', this.checkUrl);
	} else if (this._wantsHashChange) {
		this._checkUrlInterval = setInterval(this.checkUrl, this.interval);
	}

	// Determine if we need to change the base url, for a pushState link
	// opened by a non-pushState browser.
	this.fragment = fragment;
	var loc = window.location;
	var atRoot  = loc.pathname == this.options.root;

	// If we've started off with a route from a `pushState`-enabled browser,
	// but we're currently in a browser that doesn't support it...
	if (this._wantsHashChange && this._wantsPushState && !this._hasPushState && !atRoot) {
		this.fragment = this.getFragment(null, true);
		window.location.replace(this.options.root + '#' + this.fragment);
		// Return immediately as browser will do redirect to new url
		return true;

	// Or if we've started out with a hash-based route, but we're currently
	// in a browser where it could be `pushState`-based instead...
	} else if (this._wantsPushState && this._hasPushState && atRoot && loc.hash) {
		this.fragment = this.getHash().replace(routeStripper, '');
		window.history.replaceState({}, document.title, loc.protocol + '//' + loc.host + this.options.root + this.fragment);
	}

	if (!this.options.silent) {
		return this.loadUrl();
	}
	},

	// Disable Backbone.history, perhaps temporarily. Not useful in a real app,
	// but possibly useful for unit testing Routers.
	stop: function() {
	$(window).unbind('popstate', this.checkUrl).unbind('hashchange', this.checkUrl);
	clearInterval(this._checkUrlInterval);
	History.started = false;
	},

	// Add a route to be tested when the fragment changes. Routes added later
	// may override previous routes.
	route: function(route, callback) {
	this.handlers.unshift({route: route, callback: callback});
	},

	// Checks the current URL to see if it has changed, and if it has,
	// calls `loadUrl`, normalizing across the hidden iframe.
	checkUrl: function(e) {
	var current = this.getFragment();
	if (current == this.fragment && this.iframe) current = this.getFragment(this.getHash(this.iframe));
	if (current == this.fragment) return false;
	if (this.iframe) this.navigate(current);
	this.loadUrl() || this.loadUrl(this.getHash());
	},

	// Attempt to load the current URL fragment. If a route succeeds with a
	// match, returns `true`. If no defined routes matches the fragment,
	// returns `false`.
	loadUrl: function(fragmentOverride) {
	var fragment = this.fragment = this.getFragment(fragmentOverride);
	var matched = _.any(this.handlers, function(handler) {
		if (handler.route.test(fragment)) {
		handler.callback(fragment);
		return true;
		}
	});
	return matched;
	},

	// Save a fragment into the hash history, or replace the URL state if the
	// 'replace' option is passed. You are responsible for properly URL-encoding
	// the fragment in advance.
	//
	// The options object can contain `trigger: true` if you wish to have the
	// route callback be fired (not usually desirable), or `replace: true`, if
	// you wish to modify the current URL without adding an entry to the history.
	navigate: function(fragment, options) {
	if (!History.started) return false;
	if (!options || options === true) options = {trigger: options};
	var frag = (fragment || '').replace(routeStripper, '');
	if (this.fragment == frag) return;

	// If pushState is available, we use it to set the fragment as a real URL.
	if (this._hasPushState) {
		if (frag.indexOf(this.options.root) != 0) frag = this.options.root + frag;
		this.fragment = frag;
		window.history[options.replace ? 'replaceState' : 'pushState']({}, document.title, frag);

	// If hash changes haven't been explicitly disabled, update the hash
	// fragment to store history.
	} else if (this._wantsHashChange) {
		this.fragment = frag;
		this._updateHash(window.location, frag, options.replace);
		if (this.iframe && (frag != this.getFragment(this.getHash(this.iframe)))) {
		// Opening and closing the iframe tricks IE7 and earlier to push a history entry on hash-tag change.
		// When replace is true, we don't want this.
		if(!options.replace) this.iframe.document.open().close();
		this._updateHash(this.iframe.location, frag, options.replace);
		}

	// If you've told us that you explicitly don't want fallback hashchange-
	// based history, then `navigate` becomes a page refresh.
	} else {
		window.location.assign(this.options.root + fragment);
	}
	if (options.trigger) this.loadUrl(fragment);
	},

	// Update the hash location, either replacing the current entry, or adding
	// a new one to the browser history.
	_updateHash: function(location, fragment, replace) {
	if (replace) {
		location.replace(location.toString().replace(/(javascript:|#).*$/, '') + '#' + fragment);
	} else {
		location.hash = fragment;
	}
	}
});

// Backbone.View
// -------------

// Creating a Backbone.View creates its initial element outside of the DOM,
// if an existing element is not provided...
var View = Backbone.View = function(options) {
	this.cid = _.uniqueId('view');
	this._configure(options || {});
	this._ensureElement();
	this.initialize.apply(this, arguments);
	this.delegateEvents();
};

// Cached regex to split keys for `delegate`.
var delegateEventSplitter = /^(\S+)\s*(.*)$/;

// List of view options to be merged as properties.
var viewOptions = ['model', 'collection', 'el', 'id', 'attributes', 'className', 'tagName'];

// Set up all inheritable **Backbone.View** properties and methods.
_.extend(View.prototype, Events, {

	// The default `tagName` of a View's element is `"div"`.
	tagName: 'div',

	// jQuery delegate for element lookup, scoped to DOM elements within the
	// current view. This should be prefered to global lookups where possible.
	$: function(selector) {
	return this.$el.find(selector);
	},

	// Initialize is an empty function by default. Override it with your own
	// initialization logic.
	initialize: function(){},

	// **render** is the core function that your view should override, in order
	// to populate its element (`this.el`), with the appropriate HTML. The
	// convention is for **render** to always return `this`.
	render: function() {
	return this;
	},

	// Remove this view from the DOM. Note that the view isn't present in the
	// DOM by default, so calling this method may be a no-op.
	remove: function() {
	this.$el.remove();
	return this;
	},

	// For small amounts of DOM Elements, where a full-blown template isn't
	// needed, use **make** to manufacture elements, one at a time.
	//
	//     var el = this.make('li', {'class': 'row'}, this.model.escape('title'));
	//
	make: function(tagName, attributes, content) {
	var el = document.createElement(tagName);
	if (attributes) $(el).attr(attributes);
	if (content) $(el).html(content);
	return el;
	},

	// Change the view's element (`this.el` property), including event
	// re-delegation.
	setElement: function(element, delegate) {
	if (this.$el) this.undelegateEvents();
	this.$el = (element instanceof $) ? element : $(element);
	this.el = this.$el[0];
	if (delegate !== false) this.delegateEvents();
	return this;
	},

	// Set callbacks, where `this.events` is a hash of
	//
	// *{"event selector": "callback"}*
	//
	//     {
	//       'mousedown .title':  'edit',
	//       'click .button':     'save'
	//       'click .open':       function(e) { ... }
	//     }
	//
	// pairs. Callbacks will be bound to the view, with `this` set properly.
	// Uses event delegation for efficiency.
	// Omitting the selector binds the event to `this.el`.
	// This only works for delegate-able events: not `focus`, `blur`, and
	// not `change`, `submit`, and `reset` in Internet Explorer.
	delegateEvents: function(events) {
	if (!(events || (events = getValue(this, 'events')))) return;
	this.undelegateEvents();
	for (var key in events) {
		var method = events[key];
		if (!_.isFunction(method)) method = this[events[key]];
		if (!method) throw new Error('Method "' + events[key] + '" does not exist');
		var match = key.match(delegateEventSplitter);
		var eventName = match[1], selector = match[2];
		method = _.bind(method, this);
		eventName += '.delegateEvents' + this.cid;
		if (selector === '') {
		this.$el.bind(eventName, method);
		} else {
		this.$el.delegate(selector, eventName, method);
		}
	}
	},

	// Clears all callbacks previously bound to the view with `delegateEvents`.
	// You usually don't need to use this, but may wish to if you have multiple
	// Backbone views attached to the same DOM element.
	undelegateEvents: function() {
	this.$el.unbind('.delegateEvents' + this.cid);
	},

	// Performs the initial configuration of a View with a set of options.
	// Keys with special meaning *(model, collection, id, className)*, are
	// attached directly to the view.
	_configure: function(options) {
	if (this.options) options = _.extend({}, this.options, options);
	for (var i = 0, l = viewOptions.length; i < l; i++) {
		var attr = viewOptions[i];
		if (options[attr]) this[attr] = options[attr];
	}
	this.options = options;
	},

	// Ensure that the View has a DOM element to render into.
	// If `this.el` is a string, pass it through `$()`, take the first
	// matching element, and re-assign it to `el`. Otherwise, create
	// an element from the `id`, `className` and `tagName` properties.
	_ensureElement: function() {
	if (!this.el) {
		var attrs = getValue(this, 'attributes') || {};
		if (this.id) attrs.id = this.id;
		if (this.className) attrs['class'] = this.className;
		this.setElement(this.make(this.tagName, attrs), false);
	} else {
		this.setElement(this.el, false);
	}
	}

});

// The self-propagating extend function that Backbone classes use.
var extend = function (protoProps, classProps) {
	var child = inherits(this, protoProps, classProps);
	child.extend = this.extend;
	return child;
};

// Set up inheritance for the model, collection, and view.
Model.extend = Collection.extend = Router.extend = View.extend = extend;

// Backbone.sync
// -------------

// Map from CRUD to HTTP for our default `Backbone.sync` implementation.
var methodMap = {
	'create': 'POST',
	'update': 'PUT',
	'delete': 'DELETE',
	'read':   'GET'
};

// Override this function to change the manner in which Backbone persists
// models to the server. You will be passed the type of request, and the
// model in question. By default, makes a RESTful Ajax request
// to the model's `url()`. Some possible customizations could be:
//
// * Use `setTimeout` to batch rapid-fire updates into a single request.
// * Send up the models as XML instead of JSON.
// * Persist models via WebSockets instead of Ajax.
//
// Turn on `Backbone.emulateHTTP` in order to send `PUT` and `DELETE` requests
// as `POST`, with a `_method` parameter containing the true HTTP method,
// as well as all requests with the body as `application/x-www-form-urlencoded`
// instead of `application/json` with the model in a param named `model`.
// Useful when interfacing with server-side languages like **PHP** that make
// it difficult to read the body of `PUT` requests.
Backbone.sync = function(method, model, options) {
	var type = methodMap[method];

	// Default options, unless specified.
	options || (options = {});

	// Default JSON-request options.
	var params = {type: type, dataType: 'json'};

	// Ensure that we have a URL.
	if (!options.url) {
	params.url = getValue(model, 'url') || urlError();
	}

	// Ensure that we have the appropriate request data.
	if (!options.data && model && (method == 'create' || method == 'update')) {
	params.contentType = 'application/json';
	params.data = JSON.stringify(model.toJSON());
	}

	// For older servers, emulate JSON by encoding the request into an HTML-form.
	if (Backbone.emulateJSON) {
	params.contentType = 'application/x-www-form-urlencoded';
	params.data = params.data ? {model: params.data} : {};
	}

	// For older servers, emulate HTTP by mimicking the HTTP method with `_method`
	// And an `X-HTTP-Method-Override` header.
	if (Backbone.emulateHTTP) {
	if (type === 'PUT' || type === 'DELETE') {
		if (Backbone.emulateJSON) params.data._method = type;
		params.type = 'POST';
		params.beforeSend = function(xhr) {
		xhr.setRequestHeader('X-HTTP-Method-Override', type);
		};
	}
	}

	// Don't process data on a non-GET request.
	if (params.type !== 'GET' && !Backbone.emulateJSON) {
	params.processData = false;
	}

	// Make the request, allowing the user to override any Ajax options.
	return $.ajax(_.extend(params, options));
};

// Wrap an optional error callback with a fallback error event.
Backbone.wrapError = function(onError, originalModel, options) {
	return function(model, resp) {
	resp = model === originalModel ? resp : model;
	if (onError) {
		onError(originalModel, resp, options);
	} else {
		originalModel.trigger('error', originalModel, resp, options);
	}
	};
};

// Helpers
// -------

// Shared empty constructor function to aid in prototype-chain creation.
var ctor = function(){};

// Helper function to correctly set up the prototype chain, for subclasses.
// Similar to `goog.inherits`, but uses a hash of prototype properties and
// class properties to be extended.
var inherits = function(parent, protoProps, staticProps) {
	var child;

	// The constructor function for the new subclass is either defined by you
	// (the "constructor" property in your `extend` definition), or defaulted
	// by us to simply call the parent's constructor.
	if (protoProps && protoProps.hasOwnProperty('constructor')) {
	child = protoProps.constructor;
	} else {
	child = function(){ parent.apply(this, arguments); };
	}

	// Inherit class (static) properties from parent.
	_.extend(child, parent);

	// Set the prototype chain to inherit from `parent`, without calling
	// `parent`'s constructor function.
	ctor.prototype = parent.prototype;
	child.prototype = new ctor();

	// Add prototype properties (instance properties) to the subclass,
	// if supplied.
	if (protoProps) _.extend(child.prototype, protoProps);

	// Add static properties to the constructor function, if supplied.
	if (staticProps) _.extend(child, staticProps);

	// Correctly set child's `prototype.constructor`.
	child.prototype.constructor = child;

	// Set a convenience property in case the parent's prototype is needed later.
	child.__super__ = parent.prototype;

	return child;
};

// Helper function to get a value from a Backbone object as a property
// or as a function.
var getValue = function(object, prop) {
	if (!(object && object[prop])) return null;
	return _.isFunction(object[prop]) ? object[prop]() : object[prop];
};

// Throw an error when a URL is needed, and none is supplied.
var urlError = function() {
	throw new Error('A "url" property or function must be specified');
};

}).call(this);
